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    Hidden realities: Food waste from servings in mini size packaging
    (Pergamon-Elsevier Science Ltd, 2024) Doğdu, Gamze; Pekdemir, Turgay; Lakestani, Sanaz; Karabörk, Şeyda; Çavuş, Osman
    This paper provides data obtained from real-life measurement of the Food Waste (FW) associated with the services offering food in mini size (9-20 g) single-use packaging representing the impact of the difficulties in emptying the food from such packages and service characteristics. We collected discarded such food packages from commercial public eateries (a time-share thermal town, student canteen, and student refectory), quantified FW, and subjected data to statistical analysis regarding the eatery places, package characteristics, and food type. The results suggest that service style, packaging, and consumer wastefulness can cause 10-47 %, 3-11 %, and 5-37 % FW, respectively, indicating hidden part of the wastage iceberg from mini size food portions with vast implication on the food and relevant packaging sustainability. Regarding the packing, the dominant cause of FW is difficulties in emptying the food, such as the shape, size, depth, width, and material of the package. Concerning the consumer wastefulness, our measurements seem to imply that the groups with relatively higher affluency creates more FW. Our results will prove to be highly beneficial in both promoting efforts to raise awareness of not only consumers but also industry players and decision makers on the sustainability for food and relevant packaging material.
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    Industrial symbiosis: Boron waste valorization through CO2 utilization
    (Korean Institute Chemical Engineers, 2022) Çopur, Mehmet; Pekdemir, Turgay; Kocakerim, Mehmet Muhtar; Korucu, Haluk; Guliyev, Rövşen
    Various wastes being generated globally and dumped on land by mineral processing activities pose great ecological and health problems. An example is the boron mineral beneficiation solid wastes. Even greater threat is anthropogenic carbon dioxide (CO2) emissions among key causes of prevalent climate change. By this work, we propose a symbiotic solution to alleviate both environmental threats through recovering valuable boron products from boron wastes (BW), while also utilizing and sequestering CO2 stably and permanently. This article presents the results on the effect of important operation parameters for the performance of such a process within the following ranges determined by preliminary tests: temperature: 20-60 degrees C, solid-to-liquid ratio: 0.1-0.5 g/ml, reaction time: 15-120 min, stirring speed: 300-700 rpm and particle size: 150-600 mu m. CO2 gas (99.9%) flow rate was maintained continuously at 1.57 l/min under atmospheric pressure. The important findings are (1) per ton of BW production of commercially valuable either (a) 310 kg sodium penta-borate or (b) 350 kg sodium penta-borate mixed with Na2CO3, depending on the process configuration, (c) 725 kg relatively pure CaCO3, a potential source for precipitated calcium carbonate (PCC) and (d) 72 kg CO2 utilization, (2) effective parameters for CO2 utilization, in decreasing order are temperature, solid-to-liquid ratio and time, while stirring speed and particle size are ineffective within the range investigated and (3) the optimum operating conditions as: temperature: 60 degrees C, solid-to liquid ratio: 0.1 g/ml, time: 90 min, stirring speed: 500 rpm and particle size: <180 mu m.
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    Industrial symbiosis: CO2 utilization by producing disodium octaborate tetrahydrate and baking soda from borax
    (Amer Chemical Soc, 2023) Çopur, Mehmet; Şenol, Ayşe Merve; Pekdemir, Turgay; Onganer, Yavuz
    This paper proposesa novel method for CO2 capture,utilization, and sequestration (CCUS) with borax producing disodiumoctaborate tetrahydrate (Na2O & BULL;4(B2O3)& BULL;4H(2)O & EQUIV; Na2B8O13 & BULL;4H(2)O, DSOBTH) equivalent boron compoundsand sodium bicarbonate (NaHCO3). We tested the performanceof this method experimentally using aqueous ammonium (NH4 (+)) solutions in a pressurized reactor (1 L) continuouslypurged with pure (99.9%) CO2. Experimental parameters werechanged as temperature (T), 45-65 & DEG;C; solid-to-liquidratio (SLR), 0.69-0.92 g/mL; reaction time (t), 30-60 min; pressure (P), 5-30 bar;NH3 concentration (AC) 2.82-5.65 M; and steeringspeed (SS), 500 rpm. The results showed that P and T were highly influential on the performance. The best conditionsfor CO2 utilization were found as P =20 bar; T = 60 & DEG;C; SLR = 0.77 g/ml; t = 50 min; and AC = 4.76 M. Per ton of tincal, under theseconditions, produced were 0.274 ton of DSOBTH (& SIM;67% B2O3), 0.216 ton of NaHCO3 (& SIM;95% purity),0.386 ton of avoided boric acid, and 0.417 ton of avoided CO2. The total potential added value can be about $1100/ton of tincal.
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    Volumetric properties and viscosities for 1-Ethyl-3-methylimidazolium ethyl sulfate and ethylene glycol binary mixture from 293.15 K to 343.15 K at atmospheric pressure
    (Springer/Plenum Publishers, 2023) Altun, Aycan; Şara, Osman Nuri; Pekdemir, Turgay
    This study presents the results from the measurements and further analysis of densities and viscosities of pure 1-ethyl-3-methylimidazolium ethyl sulfate, EMISE, and its binary mixtures with ethylene glycol, EG, over the entire composition range. Measured at atmospheric pressure from 293.15 to 343.15 K. A first-order polynomial equation was fitted to experimental density values of the EMISE + EG binary mixtures, whereas Vogel-Fulcher-Tammann (VFT) equation was used to fit viscosity data. Volumetric and excess properties have been determined. The excess molar volumes and viscosity deviations were correlated by the Redlich-Kister polynomial equation. Additionally, several selected semi-empirical viscosity models for EMISE + EG binary mixtures were tested, and coefficients were obtained. The thermal expansion coefficients of EMISE + EG binary mixtures were calculated. The intermolecular interactions between components were discussed. The results showed that in addition to the intermolecular interactions between components, packing effects due to the molecular size caused changes in properties.